​Systemic radiation therapy

This radiation therapy, which may be used to treat certain cancers such as those of the thyroid, bone and prostate, is delivered via radioactive drugs, or radiopharmaceuticals, orally or through an injection. The thyroid absorbs most of the iodine, and the rest passes out of the body in the urine. Radioactive iodine is often given after thyroid surgery to destroy remaining cancerous tissues.

Because the radioactive materials leave the body through urine, saliva and other fluids, special precautions are taken in the days immediately following treatment so the radiation does not affect the people around the patient. These precautions may include a hospital stay, avoiding sharing utensils or other personal items, sleeping alone and limited contact with children and pregnant women.